White nose syndrome found in Horseshoe Bay bats

A fungal infection that’s deadly to bats is now present in Door County’s Horseshoe Bay Cave, according to a Wisconsin Department of Natural Resources (DNR) statement released Thursday.

A total of 14 Wisconsin sites where the insect-devouring mammals hibernate each winter “have been confirmed with the disease-causing fungus or with white nose-syndrome (WNS),” the DNR said.

“It doesn’t come as a surprise,” said Bill Schuster, director of the Door County Soil and Water Conservation Department. The discovery “doesn’t represent a significant change” in a plan developed last year for allowing a limited visits to cave, located in the town of Egg Harbor.

The cave stretches an estimated 3,000 feet back from the Niagara Escarpment under the Horseshoe Bay Golf Course. The entrance and the first 75 feet of the cave have been county owned since 2007, when golf course owners donated it to the the Door County Parks Department.

In a meeting May 20, 2014, Jennifer Redell, DNR cave and mine specialist, said the cave has the largest native bat population of any natural cave in the state. An estimated 1,250 bats hibernate there, she said.

The Door County Board approved the cave management plan last June, after Redell, Schuster, Corporation Counsel Grant Thomas and Parks Director Erik Aleson explored the first few hundred feet of the cave and worked cooperatively with the golf course owners, who have complete control of the cave beneath their land.

Redell said last year that WNS was not then present in the Horseshoe Bay Cave bat population.

Schuster said the fungus was found when the DNR conducted a survey in late February and early March of this year.

Thursday’s DNR announcement did not identify the exact locations of bat populations. However, Horseshoe Bay Cave is the only publicly known hibernation site in Door County.

“Bats at sites in Grant, Crawford, Richland, Door and Dane County have tested positive for white nose syndrome, while the fungus known to cause the disease has been confirmed in sights in Iowa, Dodge and Lafayette Counties,” the DNR said.

Only one county was known to have a colony of infected bats in a wintertime survey last year. “The original point of infection in Grant County has experienced an overall population reduction of 70-percent from pre-WNS estimates.”

Schuster said that there had not been a significant bat die-off at the Horseshoe Bay Cave this past winter.

The DNR said the agency would “continue to review public reports and respond to wildlife mortality events in order to monitor the health of Wisconsin’s bat population.”

“I don’t think (the presence of WNS) alters limited visits” to the first 300 feet of the cave, as contained in the county’s cave management plan, Schuster said.